Flooring underlayment system

ABSTRACT

A system for underlayment of a flooring has at least two foam panels having and a complementary under step portion on one side an an overstep portion on an opposite side. The understep portion has an adhesive strip with a release liner. The panels are joined by placing the overstep portion of one panel over the understep portion of an adjacent panel and removing the release liner. The overstep portion is then adhered to the overstep portion to seal the panels together. A method of grinding foam strips to form the panels is disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a continuation in part of U.S. patent application Ser. No. 17/161,817 filed on Jan. 29, 2021, which claims the benefit of U.S. Provisional Application 62/967,076 filed on Jan. 29, 2020 and are herein incorporated by reference in their entirety.

FIELD OF THE INVENTION

The invention relates to flooring underlayment systems and more particularly to foam underlayment panels.

BACKGROUND OF THE INVENTION

It is known to provide an underlayment between a sub-floor and solid finished flooring such as hardwood, engineered hardwood and composites. The purpose of the underlayment is to provide sound abatement for a room, to provide a moisture barrier between the sub-floor and the finished floor, and to provide a filler between the uneven surfaces of the subfloor and finished floor. The underlayment is frequently required by code. Many manufacturers of flooring also require the underlayment as a moisture barrier to prevent the finished floor from swelling or warping.

The underlayment may be produced from foam such as polyethylene, polyurethane, polystyrene and polypropylene. The foam is generally provided in rolls which are 36 inches to 48 inches wide. The foam is unrolled to form and cut to form a panel a panel and then joined together before the finished flooring is installed on top of the underlayment. The panels are joined together to ensure that moisture does not penetrate the flooring. One method of joining the underlayment is to abut the edges of the panels together and then adhesive tape is dispensed from a roll over the abutted edges of the panels to form a seal. This method is slow. It is also known to form panels with a lip of thin film which extends outwardly from a side edge of foam panel. An adhesive strip with a release liner extends along the other side edge of the panel. The panels are placed next to each other with the extending over the adhesive strip of the adjacent panel. The release liner is removed and the lip is sealed to create a bond preventing moisture migration. However, these systems permit gaps to be present between the panels which results in decreased effectiveness of sound abatement and moisture barrier.

SUMMARY OF THE INVENTION

A system for underlayment of a flooring on a subfloor includes a plurality of foam panels. Each of the panels has top surface and a bottom surface. The bottom surface of each panel is positioned on the subflooring and the flooring is positioned on the top surface. Each panel has a pair of sides. One side has an understep portion with an understep surface and another side has a complementary overstep portion with an overstep surface. The understep surface has an adhesive. The overstep surface of one panel is overlayed on the understep surface and joined together with adhesive. The total thickness of the overlayed overstep portion and understep portion is equal to a thickness of the foam panel. A method of making foam panels for the system includes grinding an overstep portion on one side of a top surface of the panel and a bottom surface cutting an understep portion on another side of the panel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an improved underlayment system;

FIG. 2 is a top view of a portion of a pair of panels with an overstep portion of a panel turned over; and

FIG. 3 is an end view of a pair of panels joined together;

FIG. 4 is a block diagram of a method of forming a panel;

FIG. 5 is a partial graphical view of a roller, grinding wheel and foam strip;

FIG. 6 is a partial graphical view of a roller, grinding wheel, foam strip and adhesive;

FIG. 7 is a partial graphical view of a roller, foam strip and master roll.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, an improved underlayment system 10 includes a plurality of foam panels 12 sandwiched between a finished flooring 14 and a subflooring 16. Each of the panels 12 has an understep portion 20 and a complementary overstep portion 18. The understep portion has an adhesive. Adjacent panels are joined by overlaying the overstep portion 18 onto understep portion 20 of an adjacent panel and sealing with the adhesive. Thus, provides a fast and economical way of providing excellent sealing and fast installation.

The finished flooring 14 is mounted to a top surface 22 of the foam panels 12. The finished flooring 14 may be hardwood, engineered hardwood or composite material. A bottom surface 24 each of the foam panels 12 rests on the subflooring 16. The subflooring 16 is typically plywood.

Each foam panels 12 is formed from rolls of foam material. A suitable foam material is polypropylene having a density of 1.5 to 6.0 lbs/cuff and a thickness of 1.0 to 3.0 mm However, other foams may be used such as polyethylene, polyurethane, polystyrene in various densities and thicknesses.

As shown in FIGS. 1 and 3, the understep portion 20 extends on one side 26 of each panel 12 and the overstep portion 18 extends on another side 28 of the panel 12. The understep portion 20 has an upper edge portion 30 which extends orthogonally from the top surface 22 to an undercut surface 32. The undercut surface 32 is spaced apart and parallel to the bottom surface 24. The undercut surface 32 extends to a lower edge portion 34. The lower edge portion 34 extends orthogonally between the undercut surface 32 the bottom surface 24.

The overstep portion 18 has an upper edge portion 36 extending orthogonally between the top surface 22 and an overstep surface 38. The overstep surface 38 is spaced apart and parallel to the bottom surface 24. The overcut surface 38 extends between the upper edge portion 36 and a lower edge portion 40. The lower edge portion 40 extends orthogonally downwardly to the bottom surface 24. The upper edge portion 36 of the overstep portion 18 has a height

H3

equal to the height

H2

of lower edge portion 34 of the understep portion 20. The understep portion 20 and overstep portion 18 are complementary such that when overlaid, the top surfaces 22 and bottom surfaces 24 of the panels 12 are on the same plane and have a thickness

T

and there are no gaps between the upper edge portions 30, 36 and lower edge portions 34, 40. In the preferred embodiment, the upper edge portions 30, 36 and the lower edge portions 34, 40 are of equal height H1, H2, H3, and H4 of the panel 12. The undercut surface 32 and overcut surface 38 have an identical width

w

. A width

w

of about two inches has been found to provide an excellent sound and water barrier properties.

An adhesive strip 42 extends over the understep surface parallel to the lower edge portion 34. A suitable adhesive is acrylic; however, other adhesives may be used. A release liner 44 is positioned over the adhesive. The release liner has a smooth, glossy surface facilitating removal of the liner. Alternatively, the adhesive could be placed on the overstep surface 38 or applied at the time of installation.

As shown in FIG. 2, the panels are installed by laying one panel 12 on the subflooring 16. An adjacent panel 46 is positioned with the lower edge 34 of panel 12 in abutment with the lower edge 40 of the adjacent panel 46. The overstep portion 18 is folded back and the release liner 44 is removed. The overstep 18 is then positioned on the adhesive to seal the panels 12, 44 together.

Referring to FIGS. 4-7, a method of forming the panels 12 is disclosed. In a first step, S1, a foam strip 46 as disclosed above is provided and applied to a set of rollers 48.

In the depicted embodiment of FIG. 5, the set of rollers 48 includes a lower roller 50 that acts as an anvil for a grinding wheel 52. The rollers 48 are driven by motors to move the foam strip 46. The grinding wheel 52 is positioned a specified distance from the lower roller 50 to form the undercut 32.

It should be realized that an identical grinding wheel is positioned on an opposing side of the lower roller 50 to form the overcut 38. As specified above, the undercut 32 and overcut 38 are formed on opposing edges of the foam strip 46. In step S2, the grinding wheel 52 is driven by a motor to remove the material on opposing edges of the foam strip 46. As discussed above, the foam strip 46 includes a pair of side portions 26, 28 wherein removing the top side of one edge portion to a predetermined depth and width forms undercut portion 32, and removing a bottom side of the strip forms an overcut 38 with an overcut surface having a predetermined width an upper edge and a lower edge each having a predetermined height.

In one aspect, the grinding wheel 52 is a tungsten-coated wheel having a grit of from 12 to 120. The abrasive material may include tungsten carbide, aluminum oxide or silicon carbide that has been soldered or brazed to the grinding wheel 52. In one aspect, the grinding wheel 52 may remove material having the specified height and width described above.

In step S3, adhesive 42 is applied to the undercut 32 from a dispenser and release tape 44 is applied to the adhesive to cover the adhesive strip as seen in FIG. 6.

In step S4, the foam strip 46 is rolled onto a master roll 54 for distribution to a customer. In one aspect, the master roll 54 may be a length of about 2000 feet, as best seen in FIG. 7.

In step S5, the master roll 54 may be further processed to provide specified lengths of foam strips 46 to customers for installation. Panels are formed at the time of installation by cutting a desired length from the strip and installing as disclosed above. 

1. A method of forming flooring underlayment material comprising the steps of: providing a foam strip having opposing edges and opposing top and bottom surfaces and positioning the foam strip on a set of rollers; providing at least one grinding wheel and positioning the grinding wheel a predetermined distance from one roller of the set of rollers; moving the foam strip about the rollers; rotating the grinding wheel removing material from at least one of the opposing edges of the foam strip defining either an overcut or an undercut.
 2. The method of claim 1 including the step of providing two grinding wheels positioned on opposing edges of the foam strip and on opposing top and bottom surfaces of the foam strip.
 3. The method of claim 2 including the step of rotating both of the grinding wheels removing material on the opposing edges of the foam strip defining both of the overcut and the undercut.
 4. The method of claim 1 including the step of applying an adhesive and release tape to the undercut of the foam strip.
 5. The method of claim 4 including the step of rolling the foam strip onto a master roll.
 6. The method of claim 5 including the step of cutting the master roll to a specified length.
 7. The method of claim 1, wherein a width of the undercut is equal to a width of the overcut.
 8. The method of claim 1, wherein an upper edge portion of the overcut has a height equal to a height of a lower edge portion of the undercut.
 9. The method of claim 1, wherein the upper edge portion of the undercut portion and overstep portion and the height of the lower edge portion are equal.
 10. The method of claim 1, wherein the at least one grinding wheel has a grit of from 12 to
 120. 